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1.
Mol Biol Rep ; 2020 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-32125560

RESUMO

According to the stem cell theory for cancer, hepatocellular carcinomas are sustained by a group of cancer stem cells (CSCs) which are responsible for resistance to chemotherapy. In the present study we aimed to examine lipid metabolism in cancer stem cells induced by long-term treatment with sorafenib and its relationship with acquisition of a CSC-like phenotype. Two cell lines (HepG2SF1 and Huh7SF1) were generated by incubation with a step-wise increase of sorafenib concentrations for 10 months. These cell lines displayed stem-like characteristics like increase in the expression of ABCB1A, Nanog and Oct4 as well as an E-cadherin/N-cadherin switch. HepG2SF1 and Huh7SF1 cells showed intracellular accumulation of neutral lipids, assessed by flow cytometry and confocal microscopy. The exam of lipid metabolism revealed that HepG2SF1 and Huh7SF1 cells increased the expression of the enzymes involved in de novo lipid synthesis ATP-citrate lyase (ACLY), acetyl-CoA carboxylase (ACC) and fatty acid synthase (FASN) and that of the fatty acid transporter CD36. In addition, these CSC-like cells had enhanced expression of the lipogenic transcription factor SREBP1c. Analysis of the key metabolic sensor AMP-activated kinase (AMPK) demonstrated that both AMPK phosphorylation and levels were decreased in the CSC-like cells compared to their parental cells. Interestingly, transfection of HepG2SF1 and Huh7SF1 cells with AMPK, restored the levels of the lipogenic enzymes and SREBP1c and decreased the intracellular lipid accumulation. Furthermore, AMPK transfection decreased the stemness markers and inhibited the E-cadherin/N-cadherin switch. Targeting AMPK and lipid metabolism of hepatocellular cancer stem cells is a promising strategy to face stemness and chemotherapy resistance.

2.
ACS Chem Neurosci ; 10(9): 4076-4101, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31441641

RESUMO

Here, we present a series of dual-target phosphodiesterase 9 (PDE9) and histone deacetylase (HDAC) inhibitors devised as pharmacological tool compounds for assessing the implications of these two targets in Alzheimer's disease (AD). These novel inhibitors were designed taking into account the key pharmacophoric features of known selective PDE9 inhibitors as well as privileged chemical structures, bearing zinc binding groups (hydroxamic acids and ortho-amino anilides) that hit HDAC targets. These substituents were selected according to rational criteria and previous knowledge from our group to explore diverse HDAC selectivity profiles (pan-HDAC, HDAC6 selective, and class I selective) that were confirmed in biochemical screens. Their functional response in inducing acetylation of histone and tubulin and phosphorylation of cAMP response element binding (CREB) was measured as a requisite for further progression into complete in vitro absorption, distribution, metabolism and excretion (ADME) and in vivo brain penetration profiling. Compound 31b, a selective HDAC6 inhibitor with acceptable brain permeability, was chosen for assessing in vivo efficacy of these first-in-class inhibitors, as well as studying their mode of action (MoA).

3.
ACS Chem Neurosci ; 10(3): 1765-1782, 2019 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-30525452

RESUMO

In order to determine the contributions of histone deacetylase (HDAC) isoforms to the beneficial effects of dual phosphodiesterase 5 (PDE5) and pan-HDAC inhibitors on in vivo models of Alzheimer's disease (AD), we have designed, synthesized, and tested novel chemical probes with the desired target compound profile of PDE5 and class I HDAC selective inhibitors. Compared to previous hydroxamate-based series, these molecules exhibit longer residence times on HDACs. In this scenario, shorter or longer preincubation times may have a significant impact on the IC50 values of these compounds and therefore on their corresponding selectivity profiles on the different HDAC isoforms. On the other hand, different chemical series have been explored and, as expected, some pairwise comparisons show a clear impact of the scaffold on biological responses (e.g., 35a vs 40a). The lead identification process led to compound 29a, which shows an adequate ADME-Tox profile and in vivo target engagement (histone acetylation and cAMP/cGMP response element-binding (CREB) phosphorylation) in the central nervous system (CNS), suggesting that this compound represents an optimized chemical probe; thus, 29a has been assayed in a mouse model of AD (Tg2576).

4.
Cancer Res ; 78(21): 6048-6058, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30327381

RESUMO

Zebrafish (Danio rerio) is an ideal in vivo model to study a wide variety of human cancer types. In this review, we provide a comprehensive overview of zebrafish in the cancer drug discovery process, from (i) approaches to induce malignant tumors, (ii) techniques to monitor cancer progression, and (iii) strategies for compound administration to (iv) a compilation of the 355 existing case studies showing the impact of zebrafish models on cancer drug discovery, which cover a broad scope of scenarios. Finally, based on the current state-of-the-art analysis, this review presents some highlights about future directions using zebrafish in cancer drug discovery and the potential of this model as a prognostic tool in prospective clinical studies. Cancer Res; 78(21); 6048-58. ©2018 AACR.


Assuntos
Antineoplásicos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Neoplasias/tratamento farmacológico , Animais , Animais Geneticamente Modificados , Modelos Animais de Doenças , Progressão da Doença , Descoberta de Drogas/métodos , Regulação da Expressão Gênica no Desenvolvimento , Regulação Neoplásica da Expressão Gênica , Humanos , Mutação , Transplante de Neoplasias , Peixe-Zebra
5.
JACC Heart Fail ; 6(11): 928-936, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30316938

RESUMO

OBJECTIVES: This study sought to describe the incidence, determinants, and prognostic impact of cardiogenic shock (CS) in takotsubo syndrome (TTS). BACKGROUND: TTS can be associated with severe hemodynamic instability. The prognostic implication of CS has not been well characterized in large studies of TTS. METHODS: We analyzed patients with a definitive TTS diagnosis (modified Mayo criteria) who were recruited for the National RETAKO (Registry on Takotsubo Syndrome) trial from 2003 to 2016. Cox and competing risk regression models were used to identify factors associated with mortality and recurrences. RESULTS: A total of 711 patients were included, 81 (11.4%) of whom developed CS. Male sex, QTc interval prolongation, lower left ventricular ejection fraction at admission, physical triggers, and presence of "a significant" left intraventricular pressure gradient, were associated with CS (C index = 0.85). In-hospital complication rates, including mortality, were significantly higher in patients with CS. Over a median follow-up of 284 days (interquartile range: 94 to 929 days), CS was the strongest independent predictor of long-term, all-cause mortality (hazard ratio [HR]: 5.38; 95% confidence interval [CI]: 2.60 to 8.38); cardiovascular (CV) death (sub-HR: 4.29; 95% CI: 2.40 to 21.2), and non-CV death (sub-HR: 3.34; 95% CI: 1.70 to 6.53), whereas no significant difference in the recurrence rate was observed between groups (sub-HR: 0.76; 95% CI: 0.10 to 5.95). Among patients with CS, those who received beta-blockers at hospital discharge experienced lower 1-year mortality compared with those who did not receive a beta-blocker (HR: 0.52; 95% CI: 0.44 to 0.79; pinteraction = 0.043). CONCLUSIONS: CS is not uncommon and is associated with worse short- and long-term prognosis in TTS. CS complicating TTS may constitute a marker of underlying disease severity and could identify a masked heart failure phenotype with increased vulnerability to catecholamine-mediated myocardial stunning.


Assuntos
Choque Cardiogênico/etiologia , Cardiomiopatia de Takotsubo/complicações , Idoso , Feminino , Humanos , Masculino , Prognóstico , Modelos de Riscos Proporcionais , Sistema de Registros , Fatores de Risco , Choque Cardiogênico/diagnóstico , Choque Cardiogênico/mortalidade , Cardiomiopatia de Takotsubo/diagnóstico , Cardiomiopatia de Takotsubo/mortalidade
6.
J Med Chem ; 61(15): 6546-6573, 2018 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-29890830

RESUMO

Epigenetic regulators that exhibit aberrant enzymatic activities or expression profiles are potential therapeutic targets for cancers. Specifically, enzymes responsible for methylation at histone-3 lysine-9 (like G9a) and aberrant DNA hypermethylation (DNMTs) have been implicated in a number of cancers. Recently, molecules bearing a 4-aminoquinoline scaffold were reported as dual inhibitors of these targets and showed a significant in vivo efficacy in animal models of hematological malignancies. Here, we report a detailed exploration around three growing vectors born by this chemotype. Exploring this chemical space led to the identification of features to navigate G9a and DNMT1 biological spaces: not only their corresponding exclusive areas, selective compounds, but also common spaces. Thus, we identified from selective G9a and first-in-class DNMT1 inhibitors, >1 log unit between their IC50 values, with IC50 < 25 nM (e.g., 43 and 26, respectively) to equipotent inhibitors with IC50 < 50 nM for both targets (e.g., 13). Their ADME/Tox profiling and antiproliferative efficacies, versus some cancer cell lines, are also reported.


Assuntos
Aminoquinolinas/química , Aminoquinolinas/farmacologia , Metilases de Modificação do DNA/antagonistas & inibidores , Desenho de Drogas , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Aminoquinolinas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Metilases de Modificação do DNA/química , Metilases de Modificação do DNA/metabolismo , Antígenos de Histocompatibilidade/química , Antígenos de Histocompatibilidade/metabolismo , Histona-Lisina N-Metiltransferase/química , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Conformação Proteica
7.
J Med Chem ; 61(15): 6518-6545, 2018 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-29953809

RESUMO

Using knowledge- and structure-based approaches, we designed and synthesized reversible chemical probes that simultaneously inhibit the activity of two epigenetic targets, histone 3 lysine 9 methyltransferase (G9a) and DNA methyltransferases (DNMT), at nanomolar ranges. Enzymatic competition assays confirmed our design strategy: substrate competitive inhibitors. Next, an initial exploration around our hit 11 was pursued to identify an adequate tool compound for in vivo testing. In vitro treatment of different hematological neoplasia cell lines led to the identification of molecules with clear antiproliferative efficacies (GI50 values in the nanomolar range). On the basis of epigenetic functional cellular responses (levels of lysine 9 methylation and 5-methylcytosine), an acceptable therapeutic window (around 1 log unit) and a suitable pharmacokinetic profile, 12 was selected for in vivo proof-of-concept ( Nat. Commun. 2017 , 8 , 15424 ). Herein, 12 achieved a significant in vivo efficacy: 70% overall tumor growth inhibition of a human acute myeloid leukemia (AML) xenograft in a mouse model.


Assuntos
Antineoplásicos/farmacologia , Metilases de Modificação do DNA/antagonistas & inibidores , Desenho de Drogas , Inibidores Enzimáticos/farmacologia , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacocinética , Linhagem Celular Tumoral , Metilases de Modificação do DNA/química , Metilases de Modificação do DNA/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacocinética , Antígenos de Histocompatibilidade/química , Antígenos de Histocompatibilidade/metabolismo , Histona-Lisina N-Metiltransferase/química , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Camundongos , Simulação de Acoplamento Molecular , Conformação Proteica , Ensaios Antitumorais Modelo de Xenoenxerto
8.
ACS Med Chem Lett ; 9(5): 428-433, 2018 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-29795754

RESUMO

In an effort to find novel chemical series as antifibrinolytic agents, we explore α-phenylsulfonyl-α-spiropiperidines bearing different zinc-binding groups (ZBGs) to target those metalloproteinases involved in the fibrinolytic process: MMP3 and MMP10. Surprisingly, all these new chemical series were inactive against these metalloproteinases; however, several new molecules retained the antifibrinolytic activity in a phenotypic functional assay using thromboelastometry and human whole blood. Further optimization led to compound 38 as a potent antifibrinolytic agent in vivo, three times more efficacious than the current standard-of-care (tranexamic acid, TXA) at 300 times lower dose. Finally, in order to decipher the underlying mode-of-action leading to this phenotypic response, an affinity-based probe 39 was successfully designed to identify the target involved in this response: a potentially unknown mechanism-of-action in the fibrinolytic process.

9.
Eur J Med Chem ; 150: 506-524, 2018 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-29549837

RESUMO

We have identified chemical probes that act as dual phosphodiesterase 5 (PDE5) and histone deacetylase 6 (HDAC6)-selective inhibitors (>1 log unit difference versus class I HDACs) to decipher the contribution of HDAC isoforms to the positive impact of dual-acting PDE5 and HDAC inhibitors on mouse models of Alzheimer's disease (AD) and fine-tune this systems therapeutics approach. Structure- and knowledge-based approaches led to the design of first-in-class molecules with the desired target compound profile: dual PDE5 and HDAC6-selective inhibitors. Compound 44b, which fulfilled the biochemical, functional and ADME-Tox profiling requirements and exhibited adequate pharmacokinetic properties, was selected as pharmacological tool compound and tested in a mouse model of AD (Tg2576) in vivo.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5/metabolismo , Desenho de Drogas , Desacetilase 6 de Histona/antagonistas & inibidores , Inibidores de Histona Desacetilases/farmacologia , Inibidores da Fosfodiesterase 5/farmacologia , Doença de Alzheimer/metabolismo , Linhagem Celular , Relação Dose-Resposta a Droga , Desacetilase 6 de Histona/metabolismo , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/química , Humanos , Estrutura Molecular , Neuroglia/efeitos dos fármacos , Inibidores da Fosfodiesterase 5/síntese química , Inibidores da Fosfodiesterase 5/química , Relação Estrutura-Atividade
10.
Haematologica ; 103(6): 1065-1072, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29191842

RESUMO

Regulatory T (Treg) cells can weaken antitumor immune responses, and inhibition of their function appears to be a promising therapeutic approach in cancer patients. Mice with targeted deletion of the gene encoding the Cl-/HCO3- anion exchanger AE2 (also termed SLC4A2), a membrane-bound carrier involved in intracellular pH regulation, showed a progressive decrease in the number of Treg cells. We therefore challenged AE2 as a potential target for tumor therapy, and generated linear peptides designed to bind the third extracellular loop of AE2, which is crucial for its exchange activity. Peptide p17AE2 exhibited optimal interaction ability and indeed promoted apoptosis in mouse and human Treg cells, while activating effector T-cell function. Interestingly, this linear peptide also induced apoptosis in different types of human leukemia, lymphoma and multiple myeloma cell lines and primary malignant samples, while it showed only moderate effects on normal B lymphocytes. Finally, a macrocyclic AE2 targeting peptide exhibiting increased stability in vivo was effective in mice xenografted with B-cell lymphoma. These data suggest that targeting the anion exchanger AE2 with specific peptides may represent an effective therapeutic approach in B-cell malignancies.


Assuntos
Antineoplásicos/farmacologia , Antiportadores de Cloreto-Bicarbonato/antagonistas & inibidores , Leucemia de Células B/metabolismo , Linfoma de Células B/metabolismo , Peptídeos/farmacologia , Animais , Ânions/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Leucemia de Células B/tratamento farmacológico , Leucemia de Células B/patologia , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/patologia , Camundongos , Camundongos Knockout , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
12.
J Am Heart Assoc ; 6(6)2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28572282

RESUMO

BACKGROUND: Intracerebral hemorrhage (ICH) is an acute neurological disorder with high mortality and no effective treatment. In addition to the initial bleeding event, rebleeding and hematoma expansion are associated with poor outcome in these patients. We studied the effectiveness of the new antifibrinolytic agent CM352, a short-half-life matrix metalloproteinase inhibitor, for achieving early hemostasis and improving functional recovery in a rat model of collagenase-induced ICH. METHODS AND RESULTS: ICH was induced by striatal injection of collagenase, and 1 hour later, rats received an intravenous injection of saline (n=6) or CM352 (1 mg/kg, n=6). Hematoma (basal and after 3 and 24 hours) and lesion (14 days) volumes were quantified on T2-weighted (T2) magnetic resonance images. Neurological and functional recovery was evaluated by using Bederson score and a cylinder test (basal, 24 hours, and 14 days). Early treatment (1 hour) with CM352 was efficient reducing hematoma expansion at 3 hours (P<0.01) and, more markedly, at 24 hours (P<0.01). Decreased bleeding after antifibrinolytic treatment was accompanied by reduced interleukin-6 levels at 3 hours (P<0.05) and smaller lesion volume at 14 days (P<0.01). CM352 drastically reduced sensorimotor impairment (cylinder test) after ICH in rats at 24 hours (P<0.01) and 14 days (P<0.01). Similarly, it also attenuated neurological deficit (Bederson scale) at 24 hours (P<0.01) and 14 days (P<0.01). Interestingly, late (3 hours) CM352 administration also resulted in reduced lesion size and better functional outcome. CONCLUSIONS: CM352, a new antifibrinolytic agent and matrix metalloproteinase inhibitor, effectively prevented hematoma growth and reduced lesion size in ICH in association with improved functional and neurological recovery.


Assuntos
Antifibrinolíticos/administração & dosagem , Benzamidas/administração & dosagem , Encéfalo/efeitos dos fármacos , Hemorragia Cerebral/tratamento farmacológico , Hematoma/tratamento farmacológico , Ácidos Hidroxâmicos/administração & dosagem , Inibidores de Metaloproteinases de Matriz/administração & dosagem , Acidente Vascular Cerebral/tratamento farmacológico , Animais , Antifibrinolíticos/farmacocinética , Benzamidas/farmacocinética , Encéfalo/enzimologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Morte Celular/efeitos dos fármacos , Hemorragia Cerebral/enzimologia , Hemorragia Cerebral/patologia , Hemorragia Cerebral/fisiopatologia , Modelos Animais de Doenças , Hematoma/enzimologia , Hematoma/patologia , Hematoma/fisiopatologia , Ácidos Hidroxâmicos/farmacocinética , Injeções Intravenosas , Imagem por Ressonância Magnética , Masculino , Inibidores de Metaloproteinases de Matriz/farmacocinética , Metaloproteinases da Matriz/metabolismo , Atividade Motora/efeitos dos fármacos , Ratos Sprague-Dawley , Acidente Vascular Cerebral/enzimologia , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/fisiopatologia
14.
ACS Chem Neurosci ; 8(3): 638-661, 2017 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-27936591

RESUMO

A novel systems therapeutics approach, involving simultaneous inhibition of phosphodiesterase 5 (PDE5) and histone deacetylase (HDAC), has been validated as a potentially novel therapeutic strategy for the treatment of Alzheimer's disease (AD). First-in-class dual inhibitors bearing a sildenafil core have been very recently reported, and the lead molecule 7 has proven this strategy in AD animal models. Because scaffolds may play a critical role in primary activities and ADME-Tox profiling as well as on intellectual property, we have explored alternative scaffolds (vardenafil- and tadalafil-based cores) and evaluated their impact on critical parameters such as primary activities, permeability, toxicity, and in vivo (pharmacokinetics and functional response in hippocampus) to identify a potential alternative lead molecule bearing a different chemotype for in vivo testing.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Inibidores de Histona Desacetilases/uso terapêutico , Inibidores da Fosfodiesterase 5/uso terapêutico , 3',5'-AMP Cíclico Fosfodiesterases/metabolismo , Trifosfato de Adenosina/metabolismo , Doença de Alzheimer/patologia , Animais , Linhagem Celular Transformada , GMP Cíclico/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5/metabolismo , Inibidores de Histona Desacetilases/química , Inibidores de Histona Desacetilases/farmacologia , Humanos , Leucócitos Mononucleares , Camundongos , Microssomos Hepáticos/efeitos dos fármacos , Modelos Moleculares , Neuroglia/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Inibidores da Fosfodiesterase 5/química , Inibidores da Fosfodiesterase 5/farmacologia
15.
J Med Chem ; 59(19): 8967-9004, 2016 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-27606546

RESUMO

Simultaneous inhibition of phosphodiesterase 5 (PDE5) and histone deacetylases (HDAC) has recently been validated as a potentially novel therapeutic approach for Alzheimer's disease (AD). To further extend this concept, we designed and synthesized the first chemical series of dual acting PDE5 and HDAC inhibitors, and we validated this systems therapeutics approach. Following the implementation of structure- and knowledge-based approaches, initial hits were designed and were shown to validate our hypothesis of dual in vitro inhibition. Then, an optimization strategy was pursued to obtain a proper tool compound for in vivo testing in AD models. Initial hits were translated into molecules with adequate cellular functional responses (histone acetylation and cAMP/cGMP response element-binding (CREB) phosphorylation in the nanomolar range), an acceptable therapeutic window (>1 log unit), and the ability to cross the blood-brain barrier, leading to the identification of 7 as a candidate for in vivo proof-of-concept testing ( Cuadrado-Tejedor, M.; Garcia-Barroso, C.; Sánchez-Arias, J. A.; Rabal, O.; Mederos, S.; Ugarte, A.; Franco, R.; Segura, V.; Perea, G.; Oyarzabal, J.; Garcia-Osta, A. Neuropsychopharmacology 2016 , in press, doi: 10.1038/npp.2016.163 ).


Assuntos
Inibidores de Histona Desacetilases/química , Inibidores de Histona Desacetilases/farmacologia , Inibidores da Fosfodiesterase 5/química , Inibidores da Fosfodiesterase 5/farmacologia , Acetilação/efeitos dos fármacos , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5/metabolismo , Desenho de Drogas , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/farmacocinética , Histona Desacetilases/metabolismo , Humanos , Camundongos , Modelos Moleculares , Inibidores da Fosfodiesterase 5/síntese química , Inibidores da Fosfodiesterase 5/farmacocinética
16.
J Pharmacol Exp Ther ; 358(3): 580-7, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27358483

RESUMO

Endocannabinoids act on G protein-coupled receptors that are considered potential targets for a variety of diseases. There are two different cannabinoid receptor types: ligands for cannabinoid type 2 receptors (CB2Rs) show more promise than those for cannabinoid type 1 receptors (CB1Rs) because they lack psychotropic actions. However, the complex pharmacology of these receptors, coupled with the lipophilic nature of ligands, is delaying the translational success of medications targeting the endocannabinoid system. We here report the discovery and synthesis of a fluorophore-conjugated CB2R-selective compound, CM-157 (3-[[4-[2-tert-butyl-1-(tetrahydropyran-4-ylmethyl)benzimidazol-5-yl]sulfonyl-2-pyridyl]oxy]propan-1-amine), which was useful for pharmacological characterization of CB2R by using a time-resolved fluorescence resonance energy transfer assay. This methodology does not require radiolabeled compounds and may be undertaken in homogeneous conditions and in living cells (i.e., without the need to isolate receptor-containing membranes). The affinity of the labeled compound was similar to that of the unlabeled molecule. Time-resolved fluorescence resonance energy transfer assays disclosed a previously unreported second affinity site and showed conformational changes in CB2R forming receptor heteromers with G protein-coupled receptor GPR55, a receptor for l-α-lysophosphatidylinositol. The populations displaying subnanomolar and nanomolar affinities were undisclosed in competitive assays using a well known cannabinoid receptor ligand, AM630 (1-[2-(morpholin-4-yl)ethyl]-2-methyl-3-(4-methoxybenzoyl)-6-iodoindole), and TH-chrysenediol, not previously tested on binding to cannabinoid receptors. Variations in binding parameters upon formation of dimers with GPR55 may reflect decreases in binding sites or alterations of the quaternary structure of the macromolecular G protein-coupled receptor complexes. In summary, the homogeneous binding assay described here may serve to better characterize agonist binding to CB2R and to identify specific properties of CB2R on living cells.


Assuntos
Bioensaio , Receptor CB2 de Canabinoide/metabolismo , Sítios de Ligação , Crisenos/metabolismo , Corantes Fluorescentes/química , Células HEK293 , Humanos , Indóis/metabolismo , Ligantes , Simulação de Acoplamento Molecular , Ligação Proteica , Multimerização Proteica , Estrutura Quaternária de Proteína , Receptor CB2 de Canabinoide/química , Receptores Acoplados a Proteínas-G/química , Relação Estrutura-Atividade
17.
Angew Chem Int Ed Engl ; 53(26): 6747-51, 2014 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-24841889

RESUMO

Although quinone methides are often postulated as intermediates in the biosynthesis of many polyphenolic natural products, deploying their power in a laboratory setting to achieve similar bond constructions has sometimes proven challenging. Herein, a total synthesis of the resveratrol trimer vaticanol A has been achieved through three instances of quinone methide chemistry. These operations, one of which succeeded only under very specific conditions, expediently generated its [7,5]-carbocyclic core, afforded a unique sequence for dihydrobenzofuran formation, and concurrently generated, in addition to the target molecule, a series of diastereomers reflective of many other isolates.


Assuntos
Indolquinonas/química , Estilbenos/síntese química , Produtos Biológicos/síntese química , Produtos Biológicos/química , Resveratrol , Estereoisomerismo , Estilbenos/química
18.
J Exp Biol ; 214(Pt 23): 4000-9, 2011 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-22071192

RESUMO

Neural and sensory systems adapt to prolonged stimulation to allow signaling across broader input ranges than otherwise possible with the limited bandwidth of single neurons and receptors. In the visual system, adaptation takes place at every stage of processing, from the photoreceptors that adapt to prevailing luminance conditions, to higher-order motion-sensitive neurons that adapt to prolonged exposure to motion. Recent experiments using dynamic, fluctuating visual stimuli indicate that adaptation operates on a time scale similar to that of the response itself. Further work from our own laboratory has highlighted the role for rapid motion adaptation in reliable encoding of natural image motion. Physiologically, motion adaptation can be broken down into four separate components. It is not clear from the previous studies which of these motion adaptation components are involved in the fast and dynamic response changes. To investigate the adapted response in more detail, we therefore analyzed the effect of motion adaptation using a test-adapt-test protocol with adapting durations ranging from 20 ms to 20 s. Our results underscore the very rapid rate of motion adaptation, suggesting that under free flight, visual motion-sensitive neurons continuously adapt to the changing scenery. This might help explain recent observations of strong invariance in the response to natural scenes with highly variable contrast and image structure.


Assuntos
Adaptação Ocular/fisiologia , Sensibilidades de Contraste/fisiologia , Dípteros/fisiologia , Movimento (Física) , Animais , Fenômenos Eletrofisiológicos
19.
Curr Biol ; 18(9): 661-7, 2008 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-18450449

RESUMO

Many insects perform high-speed aerial maneuvers in which they navigate through visually complex surrounds. Among insects, hoverflies stand out, with males switching from stationary hovering to high-speed pursuit at extreme angular velocities [1]. In dipterans, 50-60 large interneurons -- the lobula-plate tangential cells (LPTCs) -- detect changes in optic flow experienced during flight [2-5]. It has been predicted that large LPTC receptive fields are a requirement of accurate "matched filters" of optic flow [6]. Whereas many fly taxa have three horizontal system (HS) LPTC neurons in each hemisphere, hoverflies have four [7], possibly reflecting the more sophisticated flight behavior. We here show that the most dorsal hoverfly neuron (HS north [HSN]) is sexually dimorphic, with the male receptive field substantially smaller than in females or in either sex of blowflies. The (hoverfly-specific) HSN equatorial (HSNE) is, however, sexually isomorphic. Using complex optic flow, we show that HSN, despite its smaller receptive field, codes yaw velocity as well as HSNE. Responses to a target moving against a plain or textured background suggest that the male HSN could potentially play a role in target pursuit under some conditions.


Assuntos
Dípteros/fisiologia , Percepção de Movimento/fisiologia , Neurônios/citologia , Lobo Óptico de Animais não Mamíferos/citologia , Caracteres Sexuais , Animais , Feminino , Voo Animal/fisiologia , Masculino
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